1. Field of the Invention
This invention relates to novel copper thiobis(alkylphenol-phenolates) and to various organic compositions, such as lubricants and plastics, normally subject to oxidative degradation, containing a minor amount of said copper complexes, sufficient to impart antioxidant characteristics thereto. Additionally, this invention relates to organic compositions comprising said organic media and a minor amount of the copper compound in accordance with this disclosure thereby providing effective energy quenching stabilization and antisludging properties thereto.
in a more particular aspect this invention is directed to the above referred to novel copper phenolates and lubricant compositions containing them, which lubricant compositions include oils of lubricating viscosity, hydrocracked lubricating oils, hydraulic oils, automotive oils, gear oils, transmission fluids, waxes, greases and other forms which may be derived from mineral oils, or fractions thereof or are synthetic, of lubricants normally requiring the presence of stabilizing agents against oxidative degradation.
Also included within the scope of this invention are synergistic combinations comprising the aforesaid copper phenolates and hindered phenols and/or arylamines.
2. Description of the Prior Art
In general, the production of lubricant compositions, for example, lubricating oils produced by hydrocracking, affords a relatively high viscosity index and permits the use of certain stocks that would be unsuitable for other processes. However, hydrocracked lubricating oils tend toward poor stability against ultraviolet light degradation, rapidly forming suspended and/or precipitated insoluble material on exposure to ultraviolet light, such as sunlight, or other sources of actinic radiation. Compounds capable of absorbing ultraviolet light, for example, hydroxybenzophenones, and hydroxyphenyl benzotriazoles, have afforded some improvement in the light stability of hydrocracked oils. Conventional antioxidants have also provided some benefit. However, the copper complexes of this invention are believed to be novel.
In the literature, Heskins and Guillet in "Mechanism of Ultraviolet Stabilization of Polymers," Macromolecules 1, 97 (1968) first proposed the energy transfer mechanism of ultraviolet protection. Commercially available ultraviolet stabilizers are also listed by class and function and identified as to structure in the Kirk-Othmer Encyclopedia in "Encyclopedia of Chemical Technology," Second Edition, Vol. 21, pp. 115-122. Uri in "Thermal and Photochemical Oxidation of Polymers and Its Prevention," Chemistry and Industry, Mar. 1, 1975, pp. 199-203, cites conventional antioxidant effects (hydroperoxide decomposition and free radical capture) of bis(stilbenedithiolato)nickel and its ultraviolet inhibiting properties. In British Pat. No. 1,263,910 (1972), there is disclosed bis(stilbenedithiolato)nickel as an antioxidant for plastic materials. The compounds being useful in lube oils and functional fluids. Further, U.S. Pat. Nos. 2,703,786, 2,716,090 and 3,210,277 disclose the use of polyvalent metal (e.g. Ni) salts of alkyl phenol sulfides as oxidation inhibitors and plasticizing agents. Various polyvalent metal (e.g. nickel) compounds are disclosed in the patent literature, for example, U.S. Pat. No. 3,630,897 discloses metal salts (e.g., nickel, iron, zinc) of substituted dithiocarbamic acids and U.S. Pat. No. 3,252,910 discloses compounds such as nickel N,N-substituted dithiooxamides. U.S. Pat. No. 2,971,940 and 2,971,941 disclose nickel phenol-phenolate complexes as being useful in stabilizing polyethylene and polypropylene.
None of the foregoing disclosures, however, show organic, e.g., lubricant compositions containing the organosulfur-containing copper complexes described in accordance with this invention.